Hydraulic valves OR solid valve train

[herman maire]

I dont have a 993.... I only have the motor heh,heh.

Im sure a few of you already know that I am putting a 95 3.6 in my 72
since I already ask a bunch of questions

Here is another one....

How urgent is it needed to convert to solid valve train if the car is going to used pretty agressive OK,OK very aggresive??

I read somewhere that the hydraulic valves dont like heavy use above 5000+rpm
for long periods of time.


I am on a tight budget so would prefer not to have to change them .... I also dont need any weak spots.


Does a 964 valve train bolt up ???? Whats needed?

How much to pay used? ( I would not need the springs+retainers since I would upgrade them)

Would really apreciate any opinions

[gestalt1]

i don't know about the 993 engine but my 95 BMW M3 had hydrolic tappets and they were always making noise after a lapping session. the problem is that the oil gets pumped out of the lifter and doesn't have time to recover at the high rpms. some people put an extra 1/2 - 1 quart of oil to help but this didn't work on my car. this doesn't hurt anything but i would think you are loosing cam lift and hurting performance.

[herman maire]

Originally posted by gestalt1
i don't know about the 993 engine but my 95 BMW M3 had hydrolic tappets and they were always making noise after a lapping session. the problem is that the oil gets pumped out of the lifter and doesn't have time to recover at the high rpms. some people put an extra 1/2 - 1 quart of oil to help but this didn't work on my car. this doesn't hurt anything but i would think you are loosing cam lift and hurting performance.

I think the euro e36 M3 has a solid valve train not sure though..... I was wondering about this the other day so I am surprised the american market M3's came with the hydaulic set up ...... I hope the better oiling system on the porsche will help. If not....then out they come.
Thanks

[BReyes]

The motor does not have lifters, its nothing nor is it like a beemer motor. Is your motor scheduled for rebuild?

Why are you going to open the top end? What are your power to weight goals? What have you done with your transaxle(rebuild/new gears)?. What suspension/brakes/safety equipment are you planning on using.

Your valvetrain is very reliable. The heads flow well. Exhaust mods are helpful.You can improve your motors displacement/CR. You can change cams and valvetrain components. So long as the motor leakdown/compression numbers are good, and you adjust your driving to fit this car, your valvetrain is good to go.

You can always change your mind later. And What are the odds of that happening?

Have Fun.

Oh. I just read your signature, so lets see, uh. Yeah work on the items that give you the most bang for the buck first. If you plan to freshen the motor as a normal course of your year then, can you improve performance of your heads? sure? Are you sure now is the right time?
Regards,

[herman maire]

Thanks bernard

The main reason I was thinking of tearing into my motor is to upgrade the rod bolts. Everywhere I look I hear that they are a weak link.
Are they something to worry about?

The car will be used for 1 or 2 track weekends a month. So you think I should just stick with the HYD set up?


[b]"You can always change your mind later. And What are the odds of that happening?"[b]

Bernard thats what I am thinking but those rod bolts are really nagging at me. I am just trying to cover all bases while the motor is out. It is a nice thought to not have to think about valve ADJ though .

The only reason I would consider swapping them is if they are a weak link in my motor.

[BReyes]

Your rod bolts will be fine. You must focus on the driver my friend. Porsche production motor designers would not lose focus on reliabiliy. On a strett car with few DE events, the rod bolts would be replaced during a scheduled rebuild and along with new rings, bearings, and head work, and hardware, you would have a new motor. At that time you can spend 5x the labor hours to change things and build a race motor for additional horsepower. The reliability is a function of the design. For example your motor will hold together, even with spirited track use. It lives for that. Good. Now if you build a motor with high horsepower, you may want to freshen her up as often as you see fit to remain at your desired level competitition. If you drive the car properly, your bottom end will hold together. And as it relates to valve adj. Yes Porsches have to have their valves adjusted, ay 15k miles. You may soon be able to discern your motor's sound when your valves require adjustment.

Have your valves adjusted and new valve cover gaskets properly adjusted/installed. If you are really mechanically inclined, you can adjust your own valves with your motor out.

Real cool car you have there.

Today, I was a Rick's European (had a few minutes and was in the area), but did not get a lead on a 3.6l, as Jim was out. There was one 993 wrecked there and the drivetrain was already gone, and the roller sold.

Regards,

[Wayne 962]

Rod bolts indeed are a weak link on these motors...

-Wayne